I've actually spent quite a bit of time looking thru the Viper and Razor HD binos, trying to decide if its worth the extra $ for the tiny bit of increase in quality and optics of the Razors. I honestly don't think that you can go wrong with either series actually. Just to muddy the waters a little further, this week I looked thru the Vortex Talon 10x42s, and they looked fantastic as well, for less then half the price of the Razors, and now I'm thinking that the extra 800$ I save can go towards my other gun projects.
You should try and find a dealer who has all 3 series, and compare them all at one time to try and make your decision though as everyones eyes see thru scopes and binos a bit differently.